This is the same as what I posted on the "NYC vacation opportunity" post (an opportunity I think we would all love to take, but can't for one reason or another):
Access to the house for the Sitter:
If you have a security system, change the code to one that the sitter only will use, and change it back when you get home. Then, switch the code to yet a different code each time you have a sitter. This way you don't have to worry about whether the sitter left the code sitting out where someone could see it.
Change the lock on one door (if all your doors have the same key), and give the sitter that key. This is very easy to do -- you just get a combination of a doorknob and key set from Home Depot and switch it out with the doorknob you have on the door. Then, you can switch it back when you get home.
Another thing you could do is put the key in one of those boxes that real estate agents use, and give the sitter the code to the box. When he/she arrives, the box is hanging on the door, and he/she enters the code that allows her to get the key out and use it. Then, she puts the key back in the box and when she shuts the box it locks.
Keys:
Be aware some sitters will charge to return them. We don't do that either, but we do advertise that charge as well.
Wow. I mean, I know its an effort to have to return the keys, but I would see it as a red flag if I had to pay to get my keys back. I'd recommend just making it "free;" and incorporating the cost of the effort into every job. My sitter wants to return the keys ASAP. I think she would rather not be holding the key if I had a strange burglary here that involved no breaking of windows or doors. She doesn't know who else has a key or how trustworthy those people are, and she's smart to do it this way.
Checking up on the Sitter:
Remember that your meter will tell you when you get home if the sitter was actually testing your cat every time; what time she tested; and what the numbers were. Kind of like a nanny cam for diabetic cats.
You can also ask a friend to stop by and check on the cat every few days and report to you what the cat's condition is; how the food bowl or feeder is looking, maybe even check the sharps jar to see how many needles have been used and how many lancets. This may sound paranoid, and you would not do this with a sitter you have used several times, but if you are taking a chance because you hired this person for the first time, you may enjoy your vacation/trip more if you know your friend will tell you if something is amiss. Wouldn't it be nice to find out that everything was done just right and that you have found a sitter for the future?!
If you are really tech savvy you can put a camera outside the door that you can access remotely over the internet, and you will know what time the sitter arrived and when she left.